Backwoods Savage said:What does "burning verified well seasoned wood" mean? Verified how or by whom?
Nonprophet said:I think I may have solved the problem--I was able to get 650+ degree stove top temps last night (on a cold start!!) even though it was only 40 or so outside. I want to have another fire tonight to verify that the problem is indeed solved, and then I'll post my findings here.
NP
BotetourtSteve said:I've been a stove user for most of my life, so no lectures really needed there - yes, the stovetop thermo is a tool, but quite frankly I could do without it and still have a feel for things - when it's hot, it's hot, when it's cool, it's cool, when it needs wood, it needs wood.
I can't explain your startup problems, but there's an easy explanation as to why the stove would burn better once it got going, if those washers were removed. The Oslo has a single air inlet through the outside of the stove - a large round hole on the bottom of the stove near the back. This feeds both the primary air (the doghouse) and the secondary air to the tubes. For a given amount of draft, the more air that comes out of the doghouse, the less air will come out of the tubes, since the draft is doing its best to suck air through both routes, but they are not independent. So, the washers were probably starving the secondary tubes for preheated air by letting too much air out the doghouse. That would make it difficult to sustain good secondary combustion.Nonprophet said:Well, I'm not 100% certain that I've solved the problem, but after 2 nights of fires in the Oslo I'm pretty certain that I know what the problem was/is.
Last year when I was having problems with the Oslo in our Yurt with the marginal chimney that I had (with two 90's and a 4' horizontal run) I felt like the Oslo was starved for air and so I modified the doghouse cover by drilling a few more holes into it so as to allow more air into the firebox (as per the whole EUR/USA cover plate issue). While this did improve things somewhat, I still felt like the stove wasn't getting enough air, especially on startup when I'd have to leave the front or side door cracked or else the fire would simply go out.
So, based upon advice from another Oslo user here, I put a flat "spacer washer" on each of the two bolts that attach the doghouse cover to the stove between the stove and the DH cover so as to allow even more air to enter the firebox through the 1/8" or so gap created by the washers. It was enough of a gap to allow more air in, but not so wide as to fill up with ash. This change also made a positive difference in how the stove burned, so I left the washers there.
After posting this new thread, I thought I'd just make sure again that the air channels weren't plugged somehow (it's amazing where mice will build their nests here in the boonies.....) and so I removed the doghouse cover to check for any blockages. I used a small can of compressed air to blow through the chambers. No ash or debris was visible, nor was there any sound of anything moving around in the air chambers. When I put the DH cover back on. I decided to leave the "spacer washers" off.
Incredibly enough, this (leaving the washers off) seems to have transformed my Oslo from a pig to a thoroughbred! I started a fire shortly after in a cold stove, and within 45-50 minutes had stovetop temps (in the corners) of 640-650 degrees using the same wood and the same chimney, etc.
Frankly, I'm at a loss to explain how such a simple thing could make such a big difference, but it was nearly the same again last night as the stovetop got up to 550 very quickly (it was 30 degrees outside the first night and only 46 last night) so it would appear that the washers under the doghouse cover were the problem.
I believe that while they improved air flow with the marginal chimney in the Yurt, once in the cabin with 20' of straight pipe I think the gap under the doghouse so dispersed the air in the firebox that if negatively impacted the draft of the fire. Frankly, if I hadn't experienced this myself I wouldn't believe it--and I would not blame any of you for being skeptical either--but the truth is I had NEVER been able to get our Oslo over 575 (even when stuffed full of KD harwood...) until 2 nights ago when it easily and quickly reached 650.
So, there you have it. Any thoughts on how two flat washers could make such a big difference in how a stove operates????
NP
spendaviscpa said:Great that you got it figured out! Just to be clear, do you have the USA plate with extra holes drilled, but no washers? Is this correct? You are essentially using a EUR plate then. I’ve re-read the thread a few times and I just want to make sure I understand your final outcome! Thanks
grommal said:I can't explain your startup problems, but there's an easy explanation as to why the stove would burn better once it got going, if those washers were removed. The Oslo has a single air inlet through the outside of the stove - a large round hole on the bottom of the stove near the back. This feeds both the primary air (the doghouse) and the secondary air to the tubes. For a given amount of draft, the more air that comes out of the doghouse, the less air will come out of the tubes, since the draft is doing its best to suck air through both routes, but they are not independent. So, the washers were probably starving the secondary tubes for preheated air by letting too much air out the doghouse. That would make it difficult to sustain good secondary combustion.
jotulguy said:I also want to add, i would strongly recommend getting a new doghouse cover. It will not only give you better burn times but it will also keep your glass cleaner and make the stove easier to control. Glad to hear you found the issue though....best of luck this winter with the stove!
With the current weather conditions in PA, I don't get "raging secondaries and 650+ stovetop" with the air shut down 90% either. I DO get raging secondaries and 450-500 stovetop with the air shut as far as it will go. When it gets colder, and the draft pulls a bit harder, then I think I'll see somewhat higher temperatures, especially with very dry wood.Nonprophet said:grommal said:I can't explain your startup problems, but there's an easy explanation as to why the stove would burn better once it got going, if those washers were removed. The Oslo has a single air inlet through the outside of the stove - a large round hole on the bottom of the stove near the back. This feeds both the primary air (the doghouse) and the secondary air to the tubes. For a given amount of draft, the more air that comes out of the doghouse, the less air will come out of the tubes, since the draft is doing its best to suck air through both routes, but they are not independent. So, the washers were probably starving the secondary tubes for preheated air by letting too much air out the doghouse. That would make it difficult to sustain good secondary combustion.
Well, that's a pretty good theory, and I think you're on the right track with air being shared as part of the problem. The only issue I see with that theory is that even with the washers in we got good action out of the secondaries (they never seemed starved for air like the lower firebox did) and our glass always stayed nice and clean.
I had another fire last night with the same results--cold stove to 550 degree stovetop temps within about 45 mins, and then 600+ temps on moderate-sized reloads. It's really amazing to me how removing the washers has made such a difference--the dynamics of the fire as seen in the firebox through the front window have changed substantially and this corresponds with more heat being put out by the stove. I'm still nowhere near shutting down the air 90% and maintaining raging secondaries and 650+ stovetop temps like many other Oslo owners claim, but at least now I know that I can crank this stove when I need to and that was really my biggest concern.
NP
wendell said:... I started with 14" of glue and added 3 feet which hasn't seemed to make any difference. Checked the air control and it is working fine. Air supply in the back seems to be clear. In my case, I can get it to burn pretty well but it just takes so long to get there, I keep thinking there is something amiss. ...
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